Antifouling system comprising silicone hydrogel

ABSTRACT

A multi-layer or single layer antifouling coating system. A multi-layer coating system comprises (a) a base coating for coating a substrate, and (b) an antifouling coating composition adapted to be disposed over the base coating, the antifouling coating composition comprising a hydroxyl terminated polydimethylsiloxane, a curable polyether-containing silane of the Formula (1):
 
(R 1 O) a (R 1 ) (3-a) Si—R 2 —(Si(R 1 ) 2 O) p —Si(R 1 ) 2 —R 2 —O—(CH 2 —CHR 1 —O) q —R 1   (1)
 
where a is 1-3; R 1  is H or alkyl radical from C 1 -C 10 ; R2 is alkylene from C 2 -C 10 ; p is 1-100; and q is 1-50. The base coating composition can comprise an epoxy modified adhesion promoter. A single layer coating composition comprises a compound of Formula (4):
 
(R 1 O) a (R 1 ) 3-a —Si-M-(Si(R 1 ) 2 O) r —(Si(R 1 )(O 1/2 )(O)) t —(Si(X)(O 1/2 )(O)) v —Si(R 1 ) 2 -M-Si(OR 1 ) a (R 1 ) 3-a   (4)
 
where R 1  is H or an alkyl radical M is R 2  or oxygen; r is 0-1000; t is 1 to 20; v is 0 to 20; X is —R 2 —(N(R 1 ) 1-b (Y) b —R 2 ) c —N(R 1 ) 2-b (Y) b ; b is 0-2; c is 0-5; Y is R 1  or an organic radical with an epoxide at one terminal; and R 2  is an alkylene from C 2 -C 10 , with the proviso that at least one Y is an organic radical with an epoxide at one terminal.
 
     The respective compositions are such that the antifouling coating composition sufficiently adheres to the base coating composition without the need for a tie coat layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of PCTApplication No. PCT/US2013/042449 entitled “Antifouling SystemComprising Silicone Hydrogel” filed on May 23, 2013, which claims thebenefit of U.S. Provisional Patent Application No. 61/765,450 entitled“Antifouling System Comprising Silicone Hydrogel” filed on Feb. 15,2013, both of which are incorporated by reference herein in theirentirety.

FIELD

The present technology provides an antifouling coating composition, acoating system comprising such antifouling compositions, and articlescomprising such coating systems. The antifouling compositions andcoating systems can be utilized on articles exposed to aquatic or marineenvironments and can provide antifouling properties to the article.

BACKGROUND

Biofouling or biological fouling is the undesirable accumulation ofmicroorganisms, algae, plants, and animals on wetted surfaces. It isfound in almost all environments where aqueous liquids are in contactwith other materials. The specific and non-specific interactions ofproteins and cells with artificial surfaces form the basis of manymedical, biochemical, and biotechnological applications. In order toprevent unwanted deposition (or biofouling), any non-specific proteinand cell adsorption has to be suppressed. Preventing biological depositsof proteins or bacteria plays a key role in the field of hygiene and inkeeping clean surfaces permanently. In addition, unwanted biologicaldeposits on large wetted surfaces, such as ship hulls, water tanks,offshore rigs, etc., and in inaccessible places, such as large pipesystems, represent a major economic problem. Biofouling is on shiphulls, for example, can reduce the performance of the vessel in thewater and increase its fuel consumption, which can significantlyincrease operating cost for ship owners and operators. As much as $50billion in annual fuel saving has been realized by the shipping industrydue to the use of antifouling coatings on ship hulls.

Conventional antifoulants are mostly toxic organometallic compounds ormetals such as lead, arsenic, mercury, copper, tin, etc. Thesematerials, however, can pose risks to the environment, and efforts havebeen made to find environmentally benign technologies.

The current antifouling technologies can be generally classified intofour major categories: (1) biocidal antifouling paints containing amarine biocide, (2) non-biocidal electrical coatings, (3) non-biocidalantifouling paints, which almost exclusively function as foulingrelease, and (4) next generation fouling release products employingamphiphilic polymers or hydrogel materials to deter the settlement ofmicroorganisms on a surface. Recently, hydrogel-forming coatings, inparticular polyether-containing hydrogels, have been reported to beespecially efficient in preventing marine fouling. Poly(ethyleneglycol)has been known to inhibit adhesion of protein “glue” secreted by themicroorganism prior to establishing a thriving colony (see, for example,Merrill E. W., in Poly(ethylene glycol) Chemistry, Ed. J. M. Harris, pp199-220, Plenum Press, New York: 1992; C.-G. Gilander, Jamea N. Herron,Kap Lim, P. Claesson, P. Stenius, J. D. Andrade, in Poly(ethyleneglycol) Chemistry, Ed. J. M. Harris, Plenum Press, New York: 1992). U.S.Pub. No. 2005/0031793 and 2009/0029043 describe the syntheses ofmultifunctional star shaped polymers and their use for the preparationof thin hydrogel containing surface coatings to actively suppressunspecific protein adsorption.

Cruise et al. (Biomaterials 1998, 19, 1287-1294) and Han et al.(Macromolecules 1997, 30, 6077-6083.0) described the use ofacrylate-terminated polymers produced either from the diols or triols ofpoly(ethyleneglycol) prepolymer for the production of hydrogel layers.The acrylate-terminated prepolymer was crosslinked either on its own orwith acrylate-terminated glycerol triol in the presence of added benzyldimethylketal to form a hydrogel. Hydrogel layers with thicknesses of135 μm to 180 μm were obtained. Proposed applications for these hydrogellayers include their in vivo use, for example, to suppresspost-operative adhesion, as diffusion barriers, for the bonding orsealing of tissues, for in vivo medicamentation and their use as adirect implant, e.g. in the form of a hydrogel cell suspension, peptidehydrogel or a growth factor hydrogel. M. A. Grunlan, et al. preparedsiloxane tethered polyethylene glycol with a general formula,α-(EtO)₃Si(CH₂)₂-oligodimethylsiloxane_(n)-block-poly(ethyleneglycol)-OCH₃ via regioselective Rh-catalyzed hydrosilylation. The PEGtethered siloxane was subsequently crosslinked with silanol-terminatedpolydimethylsiloxane. The authors reported that the surfacehydrophilicity and protein resistance increased with siloxane tether andthat the flexibility of the siloxane sub-chains enabled the PEG to bemore effectively mobilized to the surface (R. Murthy, C. D. Cox, M. S.Hahn, M. A. Grunlan, Biomacromolecules 2007, 8, 3244-3252). Grunlan, etal. further reported that such coatings are resistant to marine bacteria(Polymer Preprints 2011, 52(2) 1029).

Silicone antifouling products, i.e., non-biocidal or amphiphilic orhydrogel fouling release technologies, rely on the non-stick feature todiscourage the attachment of marine organisms. Such technology isgenerally only effective when the coated vessel is moving above acertain minimum speed, and does not prevent fouling when the vessel isnot in motion or moving slowly. Because of the non-stick nature, typicalsilicone fouling release coatings do not adhere well to anticorrosioncoatings, typically an epoxy coating, that are used to coat the surfaceof an article such as a ship's hull. Strong adhesion is important tohave sufficient coating durability. To overcome the poor adhesion ofsilicone to epoxy coatings, of a tie coat layer is employed betweenepoxy and silicone coating layers. However, the use of a tie coatincreases the system cost in terms of materials and coating time, oftenadding an extra day of coating time for the additional coating.

Amphiphilic, silicone hydrogel antifouling coatings such as thosedescribed by Grunlan, employ small molecules of polyether-containingsilanes to impart protein and marine bacterial resistance. However, theuse of the polyether-containing silanes inhibits adhesion of siliconeRTV to an epoxy coating.

U.S. Pat. Nos. 4,978,704 and 4,996,112 describe a one part RTVcomposition using a mixture of an aminosilane and an epoxysilane. U.S.Pub No. 2011/0250350 describes using aminosilanes mixed withsilanol-terminated polydiorganosiloxane as a tie coat to improveadhesion. U.S. Pub. No. 2011/0250350 discloses adhesion improvementusing bis(trialkoxysilyalky)amine andN,N′-bis(trialkoxysilylalkyl)alkylenediames in a silicone tie coat.

U.S. Pat. No. 6,723,376 describes a coating process using a curablesilicon-containing functional group that is capable of latentcondensation reaction to form an undercoat and followed by coating acurable polymeric fouling inhibiting material. The curing of the foulinginhibiting material bonds the top coat to the undercoat by condensationreaction with the curable silicon-containing functional groups in theundercoat. U.S. Pat. No. 5,691,019 discloses coating a fouling releaselayer onto an adhesion promoting anticorrosive layer, where the bondingof the fouling release layer to the anticorrosive layer is enabled bythe incorporation of a curable aminosilicone fluid to the anticorrosivelayer. The aminosilicone blooms to the interface between anticorrosivelayer and fouling release layer to connect the two layers withrespective chemical reactions of amines with epoxide of the epoxy layerand alkoxysilane with the silane or silanol of polydimethylsiloxane inthe fouling release silicone layer. The incompatible nature of theaminosilicone in the epoxy formula helps the blooming of theaminosilicone. However, the incompatibility also drives up therequirement of the amount of aminosilicone. The aminosilicone moleculestend to aggregate into large globules sporadically scattering on theepoxy surface. Bonding can only occur at the sparsely area whereaminosilicone globules cover. It typically requires a very large amountof aminosilicone to fully cover the epoxy surface in order to createsufficient bonding. As a result, the use of aminosilicone for adhesionis not efficient.

SUMMARY

In one aspect, the present invention provides a coating system forcoating an article and providing a surface exhibiting an antifoulingproperty. In one aspect, the antifouling coating system comprises (a) abase coating, and (b) an antifouling coating composition, where thecoating system is substantially free of a tie-coat layer disposedbetween the base coating and the antifouling coating.

In one aspect, the present invention provides an antifouling coatingsystem comprising (a) an base coating for coating a substrate, and (b)an antifouling coating composition adapted to be disposed over the basecoating, the antifouling coating composition comprising a hydroxylterminated polydimethylsiloxane, a curable polyether-containing silaneof the Formula (1):(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹  (1)where a is 1-3; R¹ is H or an alkyl radical from C₁-C₁₀; R² is analkylene from C₂-C₁₀; p is 1-100; q is 1-50, optionally an inorganicfiller, optionally a silane cross linker, and optionally a condensationcatalyst.

In one aspect, the present invention provides an antifouling coatingsystem comprising (a) a base coating composition comprising a basecoating material and optionally a first adhesion promoter; and (b) anantifouling coating composition comprising a silane of the formula:(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹  (1)where a is 1-3; R¹ is H or alkyl radical from C₁-C₁₀; R² is alkylenefrom C₂-C₁₀; p is 1-100; q is 1-50, optionally a second adhesionpromoter, optionally an inorganic filler, optionally a silane crosslinker, and optionally a condensation catalyst.

In one embodiment, the silane is:

In one embodiment, the antifouling coating composition comprises anadhesion promoter.

In one embodiment, the base coating composition comprises an epoxymodified adhesion promoter. In one embodiment, the adhesion promoter isof the formula (4):(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(X)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)  (4)where R¹ is H or an alkyl radical; M is R² or oxygen; r is 0-1000; t is1 to 20; v is 0 to 20; X is—R²—(N(R⁷)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); c is 0-5; b is 0-2;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal.

In one embodiment, Y comprises a radical of a partially ring openeddiglycidoxy ether. In one embodiment, Y comprises a radical of partiallyring opened bisphenol A diglycidoxy ether, bisphenol F diglycidoxyether, epoxy cresol novolac, bis-(3,4-epoxycyclohexyl)adipate (e.g.,Cyracure® UVR8128), 3,4-poxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (e.g., Cyracure® UVR6110).

In one embodiment, the epoxy modified adhesion promoter is made in situby addition to a base coating composition comprising an epoxy resin atleast one molecule having the chemical formula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(Z)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical; M is R² or oxygen; r is 0-1000; t is1 to 20; v is 0 to 20; Z is —R²—(NR¹—R²)_(c)—NR¹ ₂; and c is 0-5.

In one embodiment, the epoxy modified adhesion promoter is of theformula:

In one embodiment, the antifouling coating composition comprises anadhesion promoter, and the anticorrosive composition comprises an epoxymodified adhesion promoter.

In one aspect, the present invention provides an article comprising thecoating system. In one embodiment, an article comprises a substratehaving an outer surface, a base coating composition, and an antifoulingcoating composition in accordance with aspects and embodiments of theinvention. In one embodiment, the article is substantially free of atie-coat layer disposed between the anticorrosive composition and theantifouling coating composition.

In one aspect, the present invention provides a method of coating asubstrate to provide the substrate with an antifouling surface. In oneembodiment, the method comprises (a) applying a base coating compositionto a surface of a substrate, and (b) applying an antifouling coatingcomposition onto the base coating composition, the antifouling coatingcomposition comprising a hydroxyl terminated polydimethylsiloxane, acurable polyether-containing silane of the Formula (1):(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹  (1)where a is 1-3; R¹ is H or alkyl radical from C₁-C₁₀; R2 is alkylenefrom C₂-C₁₀; p is 1-100; q is 1-50, optionally an inorganic filler,optionally a silane cross linker, and optionally a condensationcatalyst.

The removal of the tie coat not only will reduce the labor and materialcosts but also cut down the costs of shipyard and coating equipmentrentals. In addition, eliminating tie coat layer erases an extra coatingday in the dry dock, which gives additional scheduling flexibility forthe shipyards and avoids the loss of an extra day of revenue generationfor the ship operators.

In another aspect, the present invention provides a coating compositioncomprising a film forming material and a compound of the formula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(X)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 0 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); c is 0-5; b is 0-2;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal.

In another aspect, the present invention provides a compound of theformula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(X)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 0 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); c is 0-5; b is 0-2;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal.

In another aspect, the present invention provides an antifouling coatingsystem comprising a base coating composition comprising a base coatingmaterial and an epoxy modified adhesion promoter wherein the epoxymodified adhesion promoter comprises at least one molecule having thechemical formula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(X)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 0 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); b is 0-2; c is 0-5;b is 0-1; Y is R¹ or an organic radical with an epoxide at one terminal;and R² is an alkylene from C₂-C₁₀, with the proviso that at least one Yis an organic radical with an epoxide at one terminal; and anantifouling coating composition comprising a silicone elastomer andoptionally an inorganic filler, optionally a silane cross linker, andoptionally a condensation catalyst.

In yet another aspect, the present invention provides an antifoulingcoating system comprising a base coating composition comprising a basecoating material; a tie coat; and an antifouling coating composition theantifouling composition comprising a silane of the formula:(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹  (1)where a is 1-3; R¹ is H or alkyl radical from C₁-C₁₀; R² is alkylenefrom C₂-C₁₀; p is 1-100; q is 1-50, optionally an inorganic filler,optionally a silane cross linker, and optionally a condensationcatalyst.

These and other aspects are further understood with respect to thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph showing panels coated with antifoulingcompositions in accordance with embodiments of the invention compared toa panel coated with a conventional silicone compound after exposure tooceanic conditions.

DETAILED DESCRIPTION

The present invention provides an antifouling coating composition and acoating system comprising such antifouling coating composition. Inembodiments, the system is such that a tie-coat layer is not required.In one aspect, the antifouling coating system comprises (a) a basecoating composition for coating a target substrate, and (b) anantifouling coating composition. The system is substantially free of atie-coat layer between the base coating composition (a) and theantifouling coating composition (b). In another aspect, the presentinvention the antifouling coating composition comprises a single layercoating composition. The present invention also provides a novelcompound that can be used as an adhesion promoter and optimally as amaterial to provide a composition with antifouling characteristics.

The singular forms “a,” “an” and “the” include plural referents unlessthe context clearly dictates otherwise.

As used herein, the term “antifouling coating composition” refers to acoating composition that is applicable to a surface and capable ofpreventing aquatic organisms from depositing (or fouling) and growing onthe surface.

Multi-Layer Antifouling Coating System

In one aspect, the present technology provides a multi-layer antifoulingcoating system comprising (a) a base coating composition for coating atarget substrate, and (b) an antifouling coating composition. Thesystem, while comprising multiple layers, is such that it issubstantially free of a tie-coat layer between base coating and theantifouling coating.

The antifouling coating comprises (a) a curable polyether-containingsilane, and (b) a hydroxyl terminated polymer. In one embodiment, theantifouling coating further comprises (c) an adhesion promoter. Theantifouling coating composition can also comprise other optionalcomponents including, but not limited to an inorganic filler, acrosslinker, a condensation catalyst, etc., or combinations of two ormore thereof.

The curable polyether-containing silane comprises a polymer of theFormula (1):(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹  (1)where a is 1-3; R¹ is H or alkyl radical from C₁-C₁₀; R² is alkylenefrom C₂-C₁₀; p is 1-100; q is 1-50, optionally an inorganic filler,optionally a silane cross linker, and optionally a condensationcatalyst. In one embodiment, p is from 1-20; from 3-15; even from 5-12.In one embodiment, q is from 1 to 20; 3 to 15; even 5 to 10. In oneembodiment, q is 8. Here as elsewhere in the specification and claims,numerical values can be combined to form new and non-disclosed ranges.

Non-limiting examples of suitable polyether-containing silanes are thesilanes of Formula (2a) and (2b):

The hydroxyl terminated polymer comprises a material capable of reactingwith the polyether-containing silane. In one embodiment, the hydroxylterminated polymer comprises a silanol terminate polymer. An example ofa suitable silanol terminated polymer is a hydroxyl terminatedpolydimethyl siloxane. In one embodiment, the silanol terminated polymercomprises an alpha,omega-bis(SiOH) terminated polymer. In oneembodiment, the silanol terminated polymer comprises analpha,omega-bis(SiOH)polydimethylsiloxane.

In one embodiment, the hydroxyl terminated polymer comprises a polymerof the Formula (3):

where R³ is individually chosen from OH, OR¹, alkyl, and combinations oftwo or more thereof; R¹ is H or an alkyl radical (e.g., a C₁-C₁₀ alkylradical); R⁴ is individually chosen from alkyl, fluoro alkyl, alkyl arylor R⁵; R⁵ is OH or OR¹; and R⁶ is OH or OR¹, where at least one of R³,R⁴, R⁵, or R⁶ is OH. In one embodiment, R⁵ and R⁶ are OH.

The curable polyether-containing silane component can be present in theantifouling coating composition based on cured coating in an amount offrom about 0.1 weight percent to about 40 weight percent; from about 1weight percent to about 30 weight percent; even from about 5 weightpercent to about 20 weight percent. The hydroxyl terminated polymer canbe present in an amount of from about 10 weight percent to about 99weight percent; from about 20 weight percent to about 80 weight percent;even from about 40 weight percent to about 70 weight percent. Here aselsewhere in the specification and claims, numerical values can becombined to form new and non-disclosed ranges.

The antifouling coating composition can also comprise an adhesionpromoter. The adhesion promoter can be chosen from adhesion-promotingsilanes including, but not limited to,gamma-glycidoxypropyltrimethoxysilane,gamma-aminopropyltrimethoxysilane,N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane,bis-(gamma-trimethoxysilylpropyl)amine,N-beta-(aminoethyl)-gamma-aminopropylmethyldimethoxysilane,tris-(gamma-trimethoxylsilyl)isocyanurate, etc. and combinations of twoor more thereof. The adhesion promoter can also be selected from organicepoxy compounds and a combination of an epoxy compound and an adhesionpromoting silane. In one embodiments in which the antifouling coatingcomposition comprised an aminosilane and an epoxy compound.

In embodiments in which the antifouling coating composition comprises anadhesion promoter, the adhesion promoter can be present in an amount offrom about 0.1 weight percent to about 10 weight percent; from about 1weight percent to about 7 weight percent; even from about 2 weightpercent to about 5 weight percent based on cured coating.

The antifouling coating composition can optionally comprise a fillermaterial. In one embodiment, the filler is an inorganic filler. Fillerscan be particulates, fibers, pellets, aggregates, agglomerates andgranulates. Examples of suitable fillers include, but are not limitedto, clays, alumina-silicates, talc, wollastonite, mica, fumed silica,precipitated silica, calcium carbonates, etc. and combinations of two ormore thereof. Treated calcium carbonates are available under severaltrade names Ultra Pflex, Super Pflex, Hi Pflex from Specialty Minerals;Winnofil SPM, SPT from Solvay; Hubercarb lat, Hubercarb 3Qt andHubercarb W from Huber; Kotomite from ECC; and Omyacarb FT and BLP-3from Omya. Particulate materials such as any of the foregoing can bepresent in the antifouling coating composition comprising in an amountof from 0 to 70, even from 35 to 60, weight parts per 100 weight partsof the total composition based on cured coating.

The antifouling coating composition can optionally comprise acrosslinker. In one embodiment, the crosslinker comprises a silanecrosslinker. Examples of suitable crosslinkers include, but are notlimited to, an alkoxysilane, an alkoxysiloxane, an oximosilane, anoximosiloxane, an enoxysilane, an enoxysiloxane, an aminosilane, acarboxysilane, a carboxysiloxane, an alkylamidosilane, analkylamidosiloxane, an arylamidosilane, an arylamidosiloxane, analkoxyaminosilane, an alkaryaminosiloxane, an alkoxycarbamatosilane, analkoxycarbamatosiloxane, an imidatosilane, a ureidosilane, anisocyanatosilane, a thioisocyanatosilane, and combinations of two ormore thereof. Examples of suitable cross-linkers include, but are notlimited to, tetraethylorthosilicate (TEOS); methyltrimethoxysilane(MTMS); methyltriethoxysilane; vinyltrimethoxysilane;vinyltriethoxysilane; methylphenyldimethoxysilane;3,3,3-trifluoropropyltrimethoxysilane; methyltriacetoxysilane;vinyltriacetoxysilane; ethyltriacetoxysilane; di-butoxydiacetoxysilane;phenyltripropionoxysilane; methyltris(methylethylketoxime)silane;vinyltris(methylethylketoxime)silane;3,3,3-trifluoropropyltris(methylethylketoxime) silane;methyltris(isopropenoxy)silane; vinyltris(isopropenoxy)silane;ethylpolysilicate; dimethyltetraacetoxydisiloxane;tetra-n-propylorthosilicate; methyldimethoxy(ethylmethylketoximo)silane; methylmethoxybis-(ethylmethylketoximo)silane;methyldimethoxy(acetaldoximo)silane; methyldimethoxy(N-methylcarbamato)silane; ethyldimethoxy(N-methylcarbamato) silane;methyldimethoxyisopropenoxysilane; trimethoxyisopropenoxysilane;methyltri-iso-propenoxysilane; methyldimethoxy(but-2-ene-2-oxy)silane;methyldimethoxy(1-phenylethenoxy)silane;methyldimethoxy-2(1-carboethoxypropenoxy) silane;methylmethoxydi-N-methylaminosilane; vinyldimethoxymethylaminosilane;tetra-N,N-diethylaminosilane; methyldimethoxymethylaminosilane;methyltricyclohexylaminosilane; methyldimethoxyethylaminosilane;dimethyldi-N,N-dimethylaminosilane; methyldimethoxyisopropylaminosilanedimethyldi-N,N-diethylaminosilane. ethyldimethoxy(N-ethylpropionamido)silane; methyldimethoxy(N-methylacetamido)silane;methyltris(N-methylacetamido)silane;ethyldimethoxy(N-methylacetamido)silane;methyltris(N-methylbenzamido)silane;methylmethoxybis(N-methylacetamido)silane; methyldimethoxy(caprolactamo)silane; trimethoxy(N-methylacetamido)silane;methyldimethoxyethylacetimidatosilane;methyldimethoxypropylacetimidatosilane;methyldimethoxy(N,N′,N′-trimethylureido) silane;methyldimethoxy(N-allyl-N′,N′-dimethylureido) silane;methyldimethoxy(N-phenyl-N′,N′-dimethylureido)silane;methyldimethoxyisocyanatosilane; dimethoxydiisocyanatosilane;methyldimethoxythioisocyanatosilane;methylmethoxydithioisocyanatosilane, etc., and combinations of two ormore thereof.

The antifouling coating composition can optionally comprise a catalyst.In one embodiment, the crosslinker comprises a catalyst suitable forpromoting the curing of siloxanes. Advantageously, condensationcatalysts are employed since these will also catalyze the cure(hydrolysis of the alkoxysilyl groups and condensation of the resultingsilanols) of the silylated polymer component of the moisture-curablecompositions of the invention. Suitable condensation catalysts include,but are not limited to, dialkyltin dicarboxylates such as dibutyltindilaurate and dioctyltin dilaurate, tertiary amines, the stannous saltsof carboxylic acids, such as stannous octoate and stannous acetate, andthe like. Other useful catalysts include zirconium-containing,aluminum-containing, and bismuth-containing complexes such as KATXC6212, K-KAT 5218 and K-KAT 348, supplied by King Industries, Inc.,titanium chelates such as the TYZOR®. types, available from DuPontcompany, and the KR types, available from Kenrich Petrochemical, Inc.,and other organometallic catalysts, e.g., those containing a metal suchas Al, Zn, Co, Ni, Fe, etc.

The base coating is not particularly limited and can be chosen asdesired for a particular purpose or intended application. The basecoating layer may be any material suitable for forming a coating layerin an antifouling coating. Non-limiting examples include epoxy coatings,room-temperature curable silicone coatings, epoxy-silicone coatings,etc.

In one embodiment, the base coating layer is formed from an epoxy resincomposition. The epoxy coating is generally formed by curing an epoxyresin composition that comprises an epoxy resin and an amine-basedcuring agent for curing the epoxy resin.

The epoxy resin can be chosen from any suitable epoxy resin including,but not limited to, bisphenol epoxy resin, glycidylester epoxy resin,glycidylamine epoxy resin, phenol novolac epoxy resin, cresol epoxyresin, dimer acid modified epoxy resin, aliphatic epoxy resin, alicyclicepoxy resin, epoxidized oil epoxy resin, etc., and combinations of twoor more thereof. Non-limiting examples of suitable bisphenol epoxyresins include bisphenol A-type and F-type resins.

In one embodiment, the epoxy resin comprises from about 10 to about 60%by weight of the base coat composition; even from about 20 to about 50%by weight of the base coat composition.

Examples of commercially-available products that can be used as theepoxy resin include, but are not limited to, bisphenol epoxy resins suchas Epikote and Epikure resins available from Momentive SpecialtyChemicals, including, for example, Epikote 828, Epikote 834, Epikote1001, Epikote 1004, Epikote 807, Epikote 4004P, Epikote 4007P, etc.

The base coat composition also generally includes an amine-based curingagent for curing the epoxy resin. Examples of suitable amine-basedcuring agents include, for example, modified Mannich amines formed byMannich condensation reaction of phenols, formalin, and amine compounds,aliphatic polyamine, etc. In one embodiment, the amine-based curingagent may be present in an amount such that the number of amino groupsof the amine-based curing agent is chemically equivalent to the numberof epoxy groups of the epoxy resin. In another embodiment, the curingagent can be present in an amount providing an amino group to epoxygroup ratio of 0.35:1 to 0.9:1; even 0.4:1 to 0.8:1. In still anotherembodiment, the amine-based curing agent can be present in an amount ofabout 10 to about 80 parts by weight with respect to 100 parts by weightof the epoxy resin. Here as elsewhere in the specification and claims,numerical values can be combined to form new and non-disclosed ranges.

Non-limiting examples of commercially-available products that can beused as the amine-based curing agent for the epoxy resin include Epikure3292-FX60 (Momentive Specialty Chemicals), Raccamide TD966 (DainipponInk and Chemicals, Incorporated), Sunmide 307D-60 (Sanwa Chemical Co.,Ltd.), etc.

Other suitable base coating materials include, but are not limited to,room-temperature curable silicone coatings, epoxy-silicone coatings, andsilicone epoxy hybrid. These materials are not particularly limited andany compositions suitable for use in anti-fouling applications may beused to form the coating. Non-limiting examples of suitableroom-temperature curable silicone compositions include those describedin U.S. Pat. Nos. 5,449,553; 6,165,620; and 7,666,514. Non-limitingexamples of suitable epoxy-siloxane copolymers for the coating includethose described in U.S. Pat. No. 6,391,464.

In one embodiment, the base coating comprises an epoxy modified adhesionpromoter. In one embodiment, the epoxy modified adhesion promotercomprises a curable amino silicone material and an epoxy compound, wherethe epoxy modified adhesion promoter is not fully compatible with thebase polymer of the base coating. The base coating can comprise theepoxy modified adhesion promoter in an amount of from about 0.1 weightpercent to about 20 weight percent; from about 0.3 weight percent toabout 5 weight percent; even from about 0.5 weight percent to about 2weight percent. Here as elsewhere in the specification and claims,numerical values can be combined to form new and non-disclosed ranges.

In one embodiment, the epoxy modified adhesion promoter is of theFormula (4):(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(t)—(Si(X)(O_(1/2))(O))_(v)—Si(R¹)₂-M-Si(OR)_(a)(R¹)_(3-a)  (4)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 0 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); c is 0-5; b is 0-2;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal.

In one embodiment, Y comprises a radical of partially ring openedbisphenol A diglycidoxy ether, bisphenol F diglycidoxy ether, epoxycresol novolac, bis-(3,4-epoxycyclohexyl)adipate (e.g., Cyracure®UVR8128), 3,4-poxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate(e.g., Cyracure® UVR6110).

In one embodiment, the epoxy modified adhesion promoter is of theFormula (5):

The epoxy modified adhesion promoter can be prepared by the partial ringopening of the respective epoxy compound(s) with an aminosilicone. Theadhesion promoter can be premade before addition to the base coatformula or it can be made in situ by adding the respective aminosiliconeto the epoxy base coat formula directly. In one embodiment, the reactiveaminosilicone is formulated with base coat compound prior to coating.

The base coating composition can comprise other additives to the basecoating with particular properties or characteristics as desired for aparticular purpose or intended use. Suitable additives can include, forexample, an antimicrobial agent, a pigment, an anti-sagging agent, etc.

The antimicrobial agent is not particularly limited and can generally beany antimicrobial agent that is compatible with the base coatingcompositions or the resulting hydrogels. Suitable antimicrobial agentsinclude, but are not limited to, chlorhexidine salts such aschlorhexidine gluconate (CHG), parachlorometaxylenol (PCMX), triclosan,hexachlorophene, fatty acid monoesters and monoethers of glycerin andpropylene glycol such as glycerol monolaurate, glycerol monocaprylate,glycerol monocaprate, propylene glycol monolaurate, propylene glycolmonocaprylate, propylene glycol moncaprate, phenols, surfactants andpolymers that include a (C₁₂-C₂₂) hydrophobe and a quaternary ammoniumgroup or a protonated tertiary amino group, quaternary amino-containingcompounds such as quaternary silanes and polyquaternary amines such aspolyhexamethylene biguanide, silver containing compounds such as silvermetal, silver salts such as silver chloride, silver oxide and silversulfadiazine, methyl parabens, ethyl parabens, propyl parabens, butylparabens, octenidene, 2-bromo-2-nitropropane-1,3 diol, or mixtures oftwo or more thereof.

Non-limiting examples of suitable quaternary ammonium compounds andphenolic antimicrobial agents include benzalkonium chlorides and/orsubstituted benzalkonium chlorides, di(C₆-C₁₄)alkyl di short chain (C1-4alkyl and/or hydroxyalkyl) quaternaryammonium salts, N-(3-chloroallyl)hexaminium chlorides, benzethonium chloride, methylbenzethoniumchloride, and cetylpyridinium chloride. Other suitable quaternarycompounds include alkyl dimethylbenzylammonium chlorides,dialkylmethylbenzylammonium chlorides, and mixtures of two or morethereof. An example of a suitable quaternary amine containing silane isoctadecyldimethyl(3-trimethoxysilyl propyl) ammonium chloride fromGelest, Inc.

Examples of suitable pigments include, but are not limited to, talc,silica, mica, clay, calcium carbonate, kaolin, alumina white, whitecarbon, aluminum hydroxide, magnesium carbonate, barium carbonate,barium sulfate, titanium dioxide, carbon black, etc., and combinationsof two or more thereof. In one embodiment, the body pigment may bepresent in the composition in an amount, for example, of about 5 toabout 80% by weight with respect to 100% by weight of the solid contentof the base coat composition.

Examples of suitable anti-sagging agents include, but are not limitedto, organic clay wax such as amine salt, stearate, lecithinate,alkylsulfonate of Al, Ca and Zn, polyethylene wax, amide wax,hydrogenated castor oil wax, polyamide wax, a mixture of hydrogenatedcastor oil wax and polyamide wax, synthetic particulate silica,polyethylene oxide wax, etc., and combinations of two or more thereof.The anti-sagging agent may be present in an amount of about 0.1 to about5% by weight with respect to 100% by weight of the base coatcomposition.

Each of the above components can be combined with the epoxy resincomposition according to any suitable method at the desired ratiosduring preparation of the composition, by using, for example,commercially-available materials. Further, in addition to the abovecomponents, optional components such as a solvent, a liquid hydrocarbonresin, a surfactant, an anticorrosive pigment, and the like, that areused in an epoxy resin anticorrosive coating film may be added inappropriate quantities if necessary. In one embodiment, the epoxy resinbase coat composition may be provided as a two-part compositioncomprising a main agent component containing the epoxy resin and acuring agent component containing the amine-based curing agent.

The antifouling coating composition and the base coating compositionprovide an antifouling coating system. In accordance with aspects of theinvention. The antifouling coating system is substantially free of atie-coat layer disposed between the base coating and the antifoulingcoating composition. That is, in aspects of the invention, theantifouling coating composition is disposed immediately adjacent oradhered to the base coating composition. In embodiments, the antifoulingcoating composition sufficiently adheres to the base coating compositionsuch that an adhesive or binding layer such as a tie-coat layer is notrequired.

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, and (b) a base coating composition, where theantifouling coating composition comprises a silane of the Formula (1).

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, and (b) a base coating composition, where theantifouling coating composition comprises a silane of the Formula (1)and an adhesion promoter.

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, and (b) a base coating composition, where theantifouling coating composition comprises a silane of the Formula (1),and the base coating composition comprises an epoxy modified adhesionpromoter.

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, and (b) a base coating composition, where theantifouling coating composition comprises a silane of the Formula (1)and an adhesion promoter, and the base coating composition comprises anepoxy modified adhesion promoter.

Single Layer Coating System

In another aspect, the present technology provides a single layercoating system. The single layer coating system can comprise anysuitable coating or film forming material and a compound of the Formula(4):(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)—(Si(R¹)(O_(1/2))(O))_(q)—Si(X)(O_(1/2))(O)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)  (4)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 0 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)—N(R¹)_(2-b)(Y)_(b); c is 0-5; b is 0-2;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal. The coating or filmforming material can be any material as desired for a particular purposeor intended application. In one embodiment, the coating or film formingmaterial can be any material suitable as a base coating compositiondescribed above with respect to the multilayer coating system including,but not limited to, an epoxy, a curable silicone, an epoxy-silicone,etc.

The compound of the formula can provide the film with antifoulingproperties and can be suitable for use in such applications. In oneembodiment, the single layer antifouling coating system comprises acompound of the Formula (4) in an amount of from about 0.1 weightpercent to about 20 weight percent; from about 0.25 weight percent toabout 15 weight percent; from about 0.3 weight percent to about 10weight percent; from about 0.5 weight percent to about 5 weight percent;from about 0.75 weight percent to about 2 weight percent. Here aselsewhere in the specification and claims, numerical values can becombined to form new and non-disclosed ranges.

Multi-Layer Antifouling System

In still another aspect, the present technology also provides amulti-layer antifouling system. The multi-layer antifouling systemcomprises, in one embodiment, three layers: an antifouling top coat, atie coat, and an anticorrosion base coat. In one embodiment, theantifouling system comprises (a) an antifouling coating composition, (b)a tie coat, and (c) a base coating composition, where the antifoulingcoating composition comprises a silane of the Formula (1).

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, (b) a tie coat, and (c) a base coating composition,where the antifouling coating composition comprises a silane of theFormula (1) and an adhesion promoter.

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, (b) a tie coat, and (c) a base coating composition,where the antifouling coating composition comprises a silane of theFormula (1), and the base coating composition comprises an epoxymodified adhesion promoter.

In one embodiment, the antifouling system comprises (a) an antifoulingcoating composition, (b) a tie coat, and (c) a base coating composition,where the antifouling coating composition comprises a silane of theFormula (1) and an adhesion promoter, and the base coating compositioncomprises an epoxy modified adhesion promoter.

Applications

The antifouling systems (either as a multi-layer or single layer system)can be used in a variety of applications where antifouling and/orantimicrobial properties are desired. The antifouling system comprisinga silane of Formula (1) can be used to prevent the adsorption ofproteins and cells on a surface.

The base coat can be applied to and adhere to a variety of surfacesincluding, but not limited to metal (e.g., steel, iron, aluminum, etc.),fiberglass, wood, FRP, concrete etc.

The coating system can be applied to a target substrate by applying thebase coating layer to the target substrate, applying the antifoulingcomposition to the base coating layer prior to the base coating beingfully cured, and curing the coating compositions. The respective coatingcompositions can be applied by any suitable methods including, but notlimited to, by brush, by roller, by spraying, by dipping, etc. Curingcan be accomplished by any suitable curing mechanism including, forexample, moisture condensation.

The base coating and the antifouling coating can be applied to providecoating layers of a desired thickness. In one embodiment, for either themulti-layer or single coating layer systems, the base coating has athickness of from 50 micrometers to about 500 micrometers; from about100 micrometers to about 300 micrometers; even from about 150micrometers to about 200 micrometers. In one embodiment, the antifoulingcoating (for the multi-layer system) can have a thickness of from 50micrometers to about 400 micrometers; from about 100 micrometers toabout 300 micrometers; even from about 150 micrometers to about 250micrometers.

The coating systems can be employed in a variety of applicationsincluding on the surface of vessels (including but not limited to boats,yachts, motorboats, motor launches, ocean liners, tugboats, tankers,container ships and other cargo ships, submarines, and naval vessels ofall types), pipes, shore and off-shore machinery, constructions andobjects of all types such as piers, pilings, bridge substructures,water-power installations and structures, underwater oil wellstructures, nets and other aquatic culture installations, and buoys,etc.

EXAMPLES

Coated Sample Preparation

A stainless steel (304-3B) coupon of 0.037″×1″×6″ is thoroughly cleanedby soaking in isopropanol and air drying before coating. An epoxy bottomcoating is flow coated on one side of the cleaned stainless steel couponand allowed to dry and cure at ambient conditions. After the epoxybottom coat has cured for 24 hours, the silicone top coat is flow coatedon top of the epoxy coat. The top coat is allowed to dry and cure atambient conditions.

Adhesion Test

Adhesion is tested by scraping the coating with a 6″×¾″ round headedwood tongue depressor. Sufficient force is applied on the tonguedepressor to break or peel off the top coat from the epoxy bottom coat.Adhesion failure is assigned when the top coat is cleanly peeled offfrom the bottom coat. The top coat is considered to pass the adhesiontest if there is only cohesion failure at the testing spot. The adhesionis ranked from 0-5 depending upon the level of cohesion failure, with 5representing 100% cohesion failure occurred and 0 representing nocohesion failure (100% adhesion failure).

Adhesion after Water Soak

To estimate the long term adhesion performance of the coatings, selectedcoated samples are soaked in a 40° C. water bath for 1 month andadhesion is tested using the same adhesion test protocol describedabove.

Example 1: Synthesis of SiPEG

217 g of hydride terminated α,ω-(SiH)polydimethylsiloxane with a nominalstructure of ^(H)MD₁₀M^(H), 36.8 g of vinyltrimethoxysilane, 420 g oftoluene, and 0.13 g of chlorotris(triphenylphosphine)rhodium(I) ischarged to a 3-neck round bottom flask equipped with N₂ inlet,condenser, and thermometer. The solution is mixed under N₂ blanket for30 minutes before heating to 80° C. for 12 hours to afford a yellowishsolution.

120 g of the solution is charged to another 3-neck round bottom flaskequipped with an N₂ inlet, condenser, and thermometer. The reactionflask is further charged with 20.8 g polyethylene glycol monoallyl ether(eight ethylene oxide groups), 24 g toluene and 0.125 g solution ofKarstedt's catalyst in isopropanol (1% Pt). The solution is mixed underN₂ for 30 minutes before being heated to 100° C. for 2 hours. Theresulting solution contains 40% SiPEG with a chemical structure asfollows:

Example 2: Synthesis of Hybrid Adhesion Promoter

10.14 grams of Epilote 828 (from Momentive Specialty Chemicals), 42grams of toluene, and 32 grams of SF1706 (curable aminosilicone that isdimethoxysilyl terminated and amine grafted) from Momentive PerformanceMaterials is charged to a beaker and mixed at ambient for 4 hours beforeuse.

Example 3: Preparation of Epoxy Coatings

Epoxdie-containing Epon 828 (from Momentive Specialty Chemicals) iscured with an amine (Epikure 3292-FX-60 from Momentive SpecialtyChemicals) and, in some cases, the hybrid adhesion promoter of Example 2at ambient conditions. The inputs are charged to a plastic containerwith formulas according to Table 1.

TABLE 1 Example 3A Example 3B Epikure 3292-FX-60 21 12.6 Epon 828 2012.11 Hybrid adhesion promoter — 0.396 (Example 2) Xylene  4 2.4

The mixing is accomplished using a Speed Mixer DAC150 from FlackTechInc. Once the coatings are cured, water contact angle increases from 70°of standard epoxy (Example 3A) to 920 when the hybrid adhesion promoteris included in Example 3B, indicating the existing of the siliconemoiety on the coating surface.

Example 4: Preparation of Silicone RTV Compound

A silicone compound is mixed by co-extruding 50 parts of siliconepolymer (a silanol terminated polydimethylsiloxane with a nominalviscosity of 3000 cps, CRTV 942, from Momentive Performance Materials)and 50 parts of calcium carbonate filler (Albacar 5970) at 80° C. TwoRTV base compositions are then made by mixing the silicone compound withother silanol terminated polydimethylsiloxane using a Speed Mixer DAC150from FlackTech Inc. (Table 2).

TABLE 2 Example 4A Example 4B Silicone compound 62 62 CRTV942 27 17.35CRTV941 17.35 88680 7.7 7.7

Example 5: Preparation of Adhesion Promoters

Two adhesion promoters are made by mixing an epoxysilane (Silquest A-187from Momentive performance Materials) and an aminosilane (SilquestA-1100 or Silquest A-1120 from Momentive Performance Materials) atambient according to Table 3 for 24 hours before use.

TABLE 3 Example 5A Example 5B Silquest A-1100  5.8 — Silquest A-1120 — 4Silquest A-187 12.4 12.4

Example 6: Preparation of Silicone Coatings

Except as otherwise specified, silicone coatings are prepared using twomethods. In Method A, a silicone RTV, RTV11 base (uncatalyzed) andSSG4400A from Momentive Performance Materials or the formulated compoundof Example 4, is mixed with the SiPEG solution of Example 1, acommercial adhesion promoter silane, e.g., Silquest A-1100, 1200,A-1170, A-186 and A-187 (all from Momentive Performance Materials), anorganic solvent, and a dibutyltin dilaurate (DBTDL) condensationcatalyst. After each addition, the mixture is thoroughly mixed with aSpeed Mixer. In cases when more than one adhesion promoter silane isused, the mixing is applied after each silane is added to preventimmediate reaction between the two silanes (e.g. epoxy silane andaminosilne).

Method B employs a two components approach. In one component (Part A),the silicone RTV is mixed with a crosslinking silane, such as ES-40(partially condensed tetraethoxysilane) and n-propylsilicate, and in theother component (Part B), the adhesion promoter silane, organic solvent,and DBTDL is combined into a solution.

Example 7

To evaluate the impact of SiPEG to the adhesion of silicone RTV to epoxycoating, the silicone hydrogel coatings containing 0%, 5%, and 10% SiPEGwith various adhesion promoter silanes are formulated according to Table4 using Method A (Example 6). Epoxy of Example 3A is coated and driedfor 1 day before the silicone hydrogel formulas are coated and cured atambient conditions.

TABLE 4 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 7-1 7-2 7-3 7-47-5 7-6 7-7 7-8 7-9 7-10 7-11 7-12 SSG4400A 18.0 19 20 18.0 19 20 18.019 20 18.0 19 20 Ex. 1 (SiPEG 5.0 2.5 5.0 2.5 5.00 2.5 5.00 2.5solution) Siliquest A- 0.13 0.13 0.13 1100 Siliquest A- 186 Siliquest A-0.29 0.29 0.29 0.43 0.43 0.43 187 Example 5a 0.43 0.43 0.43 Example 5b0.43 0.43 0.43 Xylene 4.2 5.8 5.8 4.2 5.8 5.8 4.2 5.8 5.8 4.2 5.8 5.8DBTDL 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Total27.67 27.77 26.27 27.68 27.78 26.28 27.68 27.78 26.28 27.68 27.28 26.28% SiPEG in 10 5 0 10 5 0 10 5 0 10 5 0 dry film % silane in 2.1 2.1 2.12.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 dry film Days to N* 22 1 N* 6 1 22 11 N* N* 1 reach full adhesion

As shown in Table 4, at a fixed amount of adhesion promoter, adhesion isdelayed or never occurs in some cases with an increasing amount ofSiPEG. Thus, SiPEG appears to have a profound adverse effect on adhesionof silicone RTV to epoxy coating.

Example 8

A number of silanes are incorporated to the SiPEG containing siliconehydrogel coatings and the adhesion after 24 hour curing and thenimmersed in 40° C. water bath for 30 days. The formulations are preparedaccording to Tables 5 and 6 using Method A (Example 6).

TABLE 5 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 8-1 8-2 8-3 8-4 8-5 8-6 8-78-8 8-9 SSG4400A 18.0 19 19 19 20 18.0 19 20 20 Ex. 1 (SiPEG 5 2.5 2.52.5 5 2.5 solution) Siliquest A-1100 0.29 0.29 0.33 0.13 0.13 SiliquestA-186 0.77 0.77 Siliquest A-187 0.73 0.29 0.29 0.43 Example 5a 1.07Example 5b 1.07 0.43 Xylene 2 4.5 5.9 5.8 5.8 4.4 5.9 5.8 5.8 DBTDL0.045 0.052 0.05 0.05 0.05 0.05 0.05 0.05 0.05 % SiPEG in 10 5 5 5 0 105 0 0 dry film % silane in dry 5.0 5.0 5.0 2.1 2.1 5.1 5.1 2.1 2.1 filmAdhesion after 5 5 5 5 5 5 5 5 5 24 hr curing Adhesion after 5 5 5 5 5 55 5 5 40° C. water bath

TABLE 6 Sample Sample Sample Sample Sample Sample Sample Sample SampleSample 8-10 8-11 8-12 8-13 8-14 8-15 8-16 8-17 8-18 8-19 SSG4400A 18 1819 19 19 18 19 18 18 19 Ex. 1 5 5 2.5 2.5 2.5 5 2.5 5 5 2.5 (SiPEGsolution) Silquest 1 0.4 1 0.4 A-1170 Silquest 0.52 0.52 A-1100 Silquest0.52 0.52 0.43 0.43 A-1120 Xylene 4 4 4 4 6.5 5 6.5 5 4.2 5.8 DBTDL0.051 0.044 0.064 0.05 0.02 0.02 % SiPEG in 10 10 5 5 5 10 5 10 10 5 dryfilm % silane in 5 2 5 2 2.5 2.5 2.5 2.5 2.1 2.1 dry film Adhesion 5 5 55 5 5 5 5 5 5 after 24 hr curing Adhesion 5 5 5 5 5 5 5 5 5 5 after 40°C. water bath

Epoxy of Example 3A is coated and dried for 1 day before the siliconehydrogel formulas are coated and cured under ambient conditions. Theadhesion is measured after 24 hours curing. The cured samples are thenimmersed in a 40° C. water bath for 30 days and the adhesion is measuredagain.

Example 9: Synthesis of SiPEG-Me

217 g of hydride terminated α,ω-(SiH)polydimethylsiloxane with a nominalstructure of ^(H)MD₁₀M^(H), 36.7 g of vinyltrimethoxysilane, 420.1 g oftoluene, and 0.13 g of cholorotris(triphenylphosphine)rhodium(I) ischarged to a 3-neck round bottom flask equipped with N₂ inlet,condenser, and thermometer. The solution is mixed under a N₂ blanket for1 hour before heating to 80° C. for 12 hours to afford a yellowishsolution.

300 g of the solution is charged to another 3-neck round bottom flaskequipped with N₂ inlet, condenser, and thermometer. The reaction flaskis further charged with 53.2 g allyloxypolyethylene glycol (7.5 EOs)methyl ether, 60 g toluene and 0.205 g solution of Karstedt's catalystin isopropanol (1% Pt). The solution is mixed under N₂ for 30 minutesbefore heated to 100° C. for 2 hours. The resulting solution contains40% SiPEG-Me.

Examples 10-13

In order to evaluate the adhesion improvement imparted by the hybridadhesion promoter (Example 2), epoxy coating composition containing nohybrid adhesion promoter (Example 3A) and a composition that contains 1%hybrid adhesion promoter (Example 3B) are coated according to the coatedsample preparation method. The silicone coating is prepared using MethodB (Example 6). Two compositions of Part A are used (Example 4A andExample 4B). Part A is prepared by mixing ES-40 with Examples 4A and 4B,respectively. Part B is made by mixing 11.13 g SiPEG-Me (Example 9),7.53 g xylene, 1.41 g Silquest A-1100 and 0.19 g dibutyltin dilaurateuntil homogeneous. The Coating compositions are shown in Table 7.

TABLE 7 Example 10 Example 11 Example 12 Example 13 Epoxy coat Example3A Example 3B Example 3A Example 3B Silicone top coat PART A Example 4A20 20 Example 4B 20 20 ES-40 0.1037 0.1037 0.0798 0.0798 PART B 8.088.08 8.08 8.08 24 hr adhesion 0 5 0 5

As shown in Table 7, incorporating 1% of a hybrid adhesion promoter inthe epoxy base coat (Example 3B) greatly improved adhesion to thesilicone coats.

Example 14

The adhesion improvement of the hybrid adhesion promoter is furtherinvestigated by coating silicone compositions containing variousadhesion promoters or no adhesion promoter on the hybrid adhesionpromoter-containing epoxy (Example 3B). The silicone compositions areprepared according to Table 8 using Method A.

TABLE 8 Example Example Example Example Example 14-1 14-2 14-3 14-4 14-5SSG4400A 19 19 18 18 18 Example 1 0 2.5 5 5 5 (SiPEG solution) n-propyl-0.4 0.4 silicate Silquest 0.13 0.124 A-1100 Silquest 0.105 A-1120Silquest 0.302 A-186 Silquest 0.29 0.325 A-187 xylene 4.5 4.5 5 5 506082 0.1 0.1 0.02 0.02 0.05 (DBTDL) % adhesion 0 0 2.06 2.10 2.09promoter % SiPEG 0 5 10 10 10 Adhesion 5 5 5 5 5 after 1 week curingAdhesion 5 5 5 5 5 after 40° C. bath

Adhesion is measured after the silicone coatings are allowed to cure fora week and after the cured samples are soaked in a 40° C. water bath for30 days.

Example 15

The hybrid adhesion promoter does not have to be premade before additionto the epoxy base coat formula. Improvement in adhesion can also beachieved by simply mixing the aminosilicone with epoxy base coat formulabefore coating. In this example the amine curing agent Epikure3292-FX-60 is predissolved in xylene and then further mixed with Epon828, from Momentive Specialty Chemicals, (Epoxy 15-1) and SF1706 (Epoxy15-2). The formulas are coated on aluminum panels and allowed to cure atambient temperature (about 25° C.) for 24 hours.

After the epoxy formulas are dried for a day, the top coat formulas areprepared and coated on top of the epoxy base coat. The top coat formulascomprise two components: Component A is made by mixing the silicone baseof Example 4A with ES-40; and Component B is made by mixing the SiPEG-Mesolution of Example 9, xylene, Silquest A-1100, and adibutyltindilaurate (DBTDL) catalyst. Component A and Component B aremixed with a Speed Mixer and flow coated onto the epoxy coated panels.Table 9 illustrates the input charges. As illustrated in Table 9, theadhesion of the silicone top coats quickly developed on the epoxy basecoat containing SF1706 (Examples 15-3 and 15-4). Examples 15-1 and 15-2,on the other hand, show without SF1706, the top coats do not developadequate adhesion after 4 days even though these compositions employed amuch higher levels of adhesion promoter (Silquest A-1100).

TABLE 9 Example Example Example Example 15-1 15-2 15-3 15-4 Epoxy baseEpoxy 15-1 Epoxy 15-1 Epoxy 15-2 Epoxy 15-2 coat Epikure 3292 12.6012.60 12.60 12.60 solution xylene 4.20 4.20 4.20 4.20 Epon 828 12 1212.14 12.14 SF1706 0.152 0.152 Total 28.80 28.80 29.09 29.09 Top coatTopcoat Topcoat Topcoat Topcoat 15-1 15-2 15-3 15-4 Component A Example4A 20 20 20 20 ES-40 0.1 0.1 0.1 0.1 Component B Example 9 5.598 5.7315.902 5.970 (SiPEG-Me solution) xylene 3.966 4.058 4.177 4.226 Silquest0.849 0.626 0.331 0.216 A-1100 DBTDL 0.087 0.085 0.090 0.088 24 hradhesion 0 0 5 5 4 days 0 0 5 5 adhesion

Example 16

The use of a combination of aminosilane and organic epoxy in siliconetop coat is also found to enhance the adhesion of water soaked coatings.In this example, a small amount of Epon 828 is incorporated into asilicone top coat formulation and adhesion is determined after thesamples are immersed in a 40° C. water batch for 30 days. The epoxy basecoats are prepared by mixing Epikure 3292-FX-60, Epon 828, and,optionally, SF1706 (Example 16-3). The base coat formulations are coatedon aluminum panels and allowed to dry for 1 day. Table 9 shows the inputcharges. The top coats comprise two components: Component A comprisessilicone base of Example 4A and optionally Epon 828 (Examples 16-2 and16-3) dissolved in xylene; Component B comprises the SiPEG-Me solutionof Example 9, Silquest A-1100, ES-40 and a dibutyltindilaurate catalystmixed to homogeneous solution. Components A and B are mixed with a SpeedMixer and then coated onto the epoxy coated aluminum panels. Thecoatings are allowed to cure at ambient for a day, and the adhesion istested. The samples are then immersed in a 40° C. water bath for 30 daysbefore another adhesion test is carried out. Table 10 illustrates thatthe addition of SF1706 improves the initial adhesion of the top coat(Example 16-3). The addition of Epon 828 in the top coats improves thewater soak adhesion (Examples 16-2 and 16-3) even if the initialadhesion did not develop in 24 hours (Example 16-2).

TABLE 10 Example Example Example 16-1 16-2 16-3 Epoxy base coat Epoxy16-1 Epoxy 16-1 Epoxy 16-2 Epikure 3292 -FX-60 10.5 10.5 12.6 Epon 82810.05 10.05 12.11 xylene 4 4 4 SF1706 0.2 Top coat Topcoat TopcoatTopcoat 16-1 16-2 16-2 Component A Example 4A 20 19.08 19.08 Epon 8280.92 0.92 xylene 3.514 4.524 4.524 Component B Example 9 5.794 5.7945.794 (SiPEG-Me solution) Silquest A-1100 0.605 0.605 0.605 ES-40 0.1190.119 0.119 DBTDL 0.082 0.082 0.082 24 hr adhesion 0 0 5 adhesion after30 0 5 5 days in 40 C. water

Example 17: Ocean Test

Antifouling performance testing is carried out by immersing coatedsamples in Indian Ocean, Tuticorin, India, conducted by Sacred HeartMarine Centre. Table 11 shows the charges for each of the top coat andbase coat formulas. At ambient conditions, Epikure 3292-FX-60 is mixedin xylene until dissolved followed by further mixing with Epon 828, andif necessary SF1706 or the hybrid adhesion promoter. Steel panels 3″ by6″ are coated with epoxy base coat formulas using a brush and dried atambient conditions for a day.

Silicone top coats are prepared using two components: Component Acomprises (RTV 11 from Momentive Performance Materials, Inc.), or amixture of silicone base of Example 4A and ES-40, made by mixing the twocomponents with a Speed Mixer. Component B is made by mixing a SiPEG-Mesolution of Example 9, xylene, Silquest A-1100, Silquest A-186 (inExamples 17-1 and 17-2), and a dibutyltindilaurate catalyst. Aftercomponents A and B are mixed with a Speed Mixer, the respective siliconetop coat formula is then coated on top of the partially cured epoxy coataccording to Table 11. After curing for at least 7 days, the coatedpanels are immersed in the ocean and static immersion test is conductedfor 2 months.

TABLE 11 Example Example Example Example Example 17-1 17-2 17-3 17-417-5 Epoxy base Epoxy Epoxy Epoxy Epoxy Epoxy coat 17-1 17-2 17-3 17-417-5 Epikure 25.20 25.20 25.20 15.17 16.80 3292-FX-60 xylene 8.40 8.408.40 5.06 5.60 Example 2 0.83 SF1706 0.317 0.317 0.192 Epon 828 24.224.28 24.28 14.57 16 Top Coat Component A Example 4A 20 24 24 48 ES-400.1 0.12 0.12 0.24 RTV11 Component Topcoat Topcoat Topcoat TopcoatTopcoat B 17-1 17-2 17-3 17-4 17-5 Example 9 5.720 6.992 7.163 6.3740.000 (SiPEG-Me solution) xylene 4.213 4.929 5.070 12.934 12.203Silquest 0.138 0.166 0.259 0.485 0.344 A-1100 Silquest 0.340 0.419 A-186DBTDL 0.090 0.093 0.108 0.208 0.193

FIG. 1 shows pictures of the sample panels after 2 months in IndianOcean. The panel of Example 17-5 coated with top coat of traditionalsilicone RTV (RTV11) exhibits fouling in the form of algae and barnaclesattachment to the panel. The panels of Examples 17-1 through 17-4 coatedwith hydrogel top coats in accordance with aspects and embodiments ofthe present invention, however, remain free of fouling.

Example 18

Silicone hydrogel top coats can also be used in a three-layer coatingsystem, such as: anticorrosion epoxy coat/tie coat/top coat. Thisexample illustrates the usefulness of the disclosed silicone hydrogeltop coat in a tie coat-containing antifouling system.

A substrate panel is coated with an anticorrosion epoxy primerInterProtect® 2000E (from International Paint) and a then tie coat layerIntersleek®731 (from International Paint) according to themanufacturer's recommended procedure of mixing 3 parts of component Aand 1 part of component B of InterProtect® 2000E mixed and coating witha brush. A one to one ratio of component A and component B ofIntersleek®731 are mixed and coated, over the anticorrosion coatinglayer using a brush. Each coating is allowed to dry and cure at ambientconditions for a day before another coating is applied. The siliconehydrogel top coat is applied on top of Intersleek®731 and adhesion wastest was conducted after the top coat is allowed to cure at ambientconditions for a day.

The top coat formulation is made by preparing components A and Bseparately. In component A, 0.45 g Epon 828 (from Momentive SpecialtyChemicals) is dissolved in 5.2 g of xylene and then mixed with 19.06 g asilicone base compound of Example 4A using a Speed Mixer. In componentB, 5.474 g a SiPEG-Me solution of Example 9, 0.164 g Silquest A-1100,0.15 g ES-40, and 0.097 g dibutyltindilaulate are mixed untilhomogeneous. Components A and B are mixed with Speed Mixer beforeapplying the composition with a brush onto the partially cured tie coatlayer

After allowing for 24 hours curing, the adhesion is tested and foundstrong bonding between silicone hydrogel top coat and Intersleek® 731tie coat.

While the invention has been described with reference to variousexemplary embodiments, it will be appreciated that modifications mayoccur to those killed in the art, and the present application isintended to cover such modifications and inventions as fall within thespirit of the invention.

What is claimed is:
 1. An antifouling coating system comprising: a basecoating composition comprising a base coating material and a firstadhesion promoter comprising an epoxy modified adhesion promoter; and anantifouling coating composition comprising a silane of the formula:(R¹O)_(a)(R¹)_((3-a))Si—R²—(Si(R¹)₂O)_(p)—Si(R¹)₂—R²—O—(CH₂—CHR¹—O)_(q)—R¹where a is 1-3; R¹ is H or alkyl radical from C₁-C₁₀; R² is alkylenefrom C₂-C₁₀; p is 1-100; q is 1-50, a second adhesion promoter,optionally an inorganic filler, optionally a silane cross linker, andoptionally a condensation catalyst.
 2. The antifouling coating system ofclaim 1, wherein R¹ is a C₁-C₁₀ alkyl.
 3. The antifouling system ofclaim 1, wherein R¹ is methyl.
 4. The antifouling system of claim 1,wherein the silane is:


5. The antifouling system of claim 1, wherein the antifoulingcomposition comprises a hydroxyl terminated polymer that is capable ofreacting with the silane.
 6. The antifouling system of claim 5, whereinthe hydroxyl terminated polymer is a silanol terminated polymer.
 7. Theantifouling system of claim 5, wherein the hydroxyl terminated polymeris of the formula:

where R³ is individually chosen from OH, OR¹, alkyl, and combinations oftwo or more thereof; R¹ is H or an alkyl radical; R⁴ is individuallychosen from an alkyl, an aryl fluoro alkyl, a fluoro aryl, an alkyl arylor R⁵; and R⁵ and R⁶ are individually OH or OR¹, with at least one ofR³, R⁴, R⁵, R⁶, or a combination thereof being OH.
 8. The antifoulingsystem of claim 1, wherein the epoxy modified adhesion promotercomprises at least one molecule having the chemical formula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(r)(Si(R¹)(O_(1/2)R¹)(O))_(t)—(Si(X)(O_(1/2)R¹(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical, M is R² or oxygen; r is 0-1000; t is1 to 20; v is 1 to 20; X is—R²—(N(R¹)_(1-b)(Y)_(b)—R²)_(c)-MR¹)_(2-b)(Y)_(b); b is 0-2; c is 0-5; Yis R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal.
 9. The antifoulingsystem of claim 8, wherein the epoxy modified adhesion promoter is madein situ by addition to a base coating composition comprising an epoxyresin at least one molecule having the chemical formula:(R₁O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O_(r)(Si(R¹)(O_(1/2)R¹)(O))_(t)—(Si(Z)(O_(1/2)R¹)(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical; M is R² or oxygen; r is 0-1000; t is1 to 20; v is 0 to 20; Z is —R²—(NR¹—R₂)_(c)—NR¹ ₂; and c is 0-5. 10.The antifouling system of claim 8, wherein Y comprises a radical ofpartially ring opened bisphenol A diglycidoxy ether, bisphenol Fdiglycidoxy ether, epoxy cresol novolac,bis-(3,4-epoxycyclohexyl)adipate,3,4-poxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, or acombination of two or more therof.
 11. The antifouling system of claim8, wherein the epoxy modified adhesion promoter is of the formula:


12. The antifouling system of claim 1, comprising a second adhesionpromoter chosen from gamma-aminpropyltriethoxysilane,N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane,gamma-glycidoxypropyltrimethoxysilane,beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, andbis-(gamma-trimethoxysilylpropyl)amine.
 13. The antifouling system ofclaim 1, wherein the second adhesion promoter comprises a combination ofan aminosilane and an epoxy compound.
 14. The antifouling system ofclaim 1, wherein the antifouling coating composition comprises a filler,a crosslinker, and/or a condensation catalyst.
 15. The antifoulingsystem of claim 1, wherein the system is substantially free of a tiecoat material.
 16. The antifouling system of claim 1, wherein the systemcomprises a tie coat layer disposed between the base coating and theantifouling coating.
 17. An article comprising the coating system ofclaim 1, the article comprising a base coat layer formed from the basecoating composition disposed on a surface of the article, and anantifouling coating layer disposed on the base coat layer.
 18. Thearticle of claim 17, wherein the coating system is substantially free ofa tie coat layer disposed between the base coat layer and theantifouling coating layer.
 19. An antifouling coating system comprising:a base coating composition comprising a base coating material and anepoxy modified adhesion promoter wherein the epoxy modified adhesionpromoter comprises at least one molecule having the chemical formula:(R¹O)_(a)(R¹)_(3-a)—Si-M-(Si(R¹)₂O)_(t)—(Si(R¹)(O_(1/2)R¹)(O))_(t)(Si(X)(O_(1/2)R¹)(O))_(v)—Si(R¹)₂-M-Si(OR¹)_(a)(R¹)_(3-a)where R¹ is H or an alkyl radical M is R² or oxygen; r is 0-1000; t is 1to 20; v is 1 to 20; X is—R₂—(N(R¹)_(1-b)(Y)_(b)—R₂)_(c)—N(R¹)_(2-b)(Y)_(b); b is 0-2; c is 0-5;Y is R¹ or an organic radical with an epoxide at one terminal; and R² isan alkylene from C₂-C₁₀, with the proviso that at least one Y is anorganic radical with an epoxide at one terminal; and an antifoulingcoating composition comprising a silicone elastomer and optionally aninorganic filler, optionally a silane cross linker, and optionally acondensation catalyst.
 20. The antifouling system of claim 19, wherein Ycomprises a radical of partially ring opened bisphenol A diglycidoxyether, bisphenol F diglycidoxy ether, epoxy cresol novolac,bis-(3,4-epoxycyclohexyl)adipate,3,4-poxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, or acombination of two or more thereof.
 21. The antifouling system of claim19, wherein the epoxy modified adhesion promoter having the formula: